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From: Michael Walle <michael-QKn5cuLxLXY@public.gmane.org>
To: Vladimir Oltean <olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	lkml <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Shawn Guo <shawnguo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Esben Haabendal <eha-/iRVSOupHO4@public.gmane.org>,
	angelo-BIYBQhTR83Y@public.gmane.org,
	andrew.smirnov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	"Gustavo A. R. Silva"
	<gustavo-L1vi/lXTdts+Va1GwOuvDg@public.gmane.org>,
	Wei Chen <weic-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>,
	Mohamed Hosny <mhosny-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>,
	peng.ma-3arQi8VN3Tc@public.gmane.org
Subject: Re: [PATCH v3 06/12] spi: spi-fsl-dspi: Replace interruptible wait queue with a simple completion
Date: Tue, 17 Mar 2020 12:24:49 +0100	[thread overview]
Message-ID: <52ce52ed4f045c4276dfb885ed29e835@walle.cc> (raw)
In-Reply-To: <8c22cb70b7c0acb6769e0c68540ab523-QKn5cuLxLXY@public.gmane.org>

Am 2020-03-16 18:15, schrieb Michael Walle:
>>> dd: /dev/mtd0: Input/output error
>> 
>> I don't really have a SPI flash connected to DSPI on any LS1028A 
>> board.
> 
> I'm already debugging it again.

Ok now maybe a more experienced kernel developer could have a look at 
this.

(1) the error is EIO because the actual_length doesn't match the 
expected
     length
(2) I've put trace_printk() where the actual_length is modified:
     in dspi_fifo_write()

         /* Update total number of bytes that were transferred */
         bytes_sent = dspi->words_in_flight * dspi->oper_word_size;
         msg->actual_length += bytes_sent;
         trace_printk("msg=%px actual_length=%d bytes_sent=%d 
word_in_flight=%d oper_word_size=%d\n",
                         msg, msg->actual_length,
                         bytes_sent, dspi->words_in_flight,
                         dspi->oper_word_size);
         dspi->progress += bytes_sent / DIV_ROUND_UP(xfer->bits_per_word, 
8);

    At the start of the foreach transfer loop in 
dspi_transfer_one_message():

         list_for_each_entry(transfer, &message->transfers, 
transfer_list) {
                 trace_printk("%d transfer->length=%d\n", i++, 
transfer->len);
                 dspi->cur_transfer = transfer;

    And at the end of this function:


         }
         trace_printk("returning actual_length=%d\n", 
message->actual_length);

         message->status = status;
         spi_finalize_current_message(ctlr);

         return status;

(3) The trace is attached at the end of this mail. There is a good case 
and the
     bad one. What I've noticed (besides returning the wrong count, eg 
13, which
     seems to be the first one) is the preempt-depth which is always none 
in the
     bad case. In all transfers before, the preempt-depth is 1. The flags 
are
     usually "d.h1", sometimes "d.H1" and in case of the error "d.H.".
     I also don't know why the fifo_write() with actual_length=13 is 
traced after
     all the ones printed inside the interrupt handler. Also something 
seems to
     be off with the words_in_flight and oper_word_size in the bad case.

     So besides the flags.. I still think there is a race between the
     dspi_fifo_write() call in transfer_one_message and the interrupt 
handler
     for the shared data like words_in_flight and oper_word_size.


good one:
               dd-1259  [000] ....  3383.499863: 
dspi_transfer_one_message: 0 transfer->length=1
               dd-1259  [000] ....  3383.499886: dspi_fifo_write: 
msg=ffff800011973840 actual_length=1 bytes_sent=1 word_in_flight=1 
oper_word_size=1
               dd-1259  [000] ....  3383.499891: 
dspi_transfer_one_message: 1 transfer->length=3
               dd-1259  [000] ....  3383.499915: dspi_fifo_write: 
msg=ffff800011973840 actual_length=4 bytes_sent=3 word_in_flight=3 
oper_word_size=1
               dd-1259  [000] ....  3383.499920: 
dspi_transfer_one_message: 2 transfer->length=1
               dd-1259  [000] ....  3383.499940: dspi_fifo_write: 
msg=ffff800011973840 actual_length=5 bytes_sent=1 word_in_flight=1 
oper_word_size=1
               dd-1259  [000] ....  3383.499946: 
dspi_transfer_one_message: 3 transfer->length=64
               dd-1259  [000] d.h1  3383.499973: dspi_fifo_write: 
msg=ffff800011973840 actual_length=21 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.h1  3383.499993: dspi_fifo_write: 
msg=ffff800011973840 actual_length=29 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.h1  3383.500013: dspi_fifo_write: 
msg=ffff800011973840 actual_length=37 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.h1  3383.500032: dspi_fifo_write: 
msg=ffff800011973840 actual_length=45 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.h1  3383.500051: dspi_fifo_write: 
msg=ffff800011973840 actual_length=53 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.h1  3383.500070: dspi_fifo_write: 
msg=ffff800011973840 actual_length=61 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.h1  3383.500089: dspi_fifo_write: 
msg=ffff800011973840 actual_length=69 bytes_sent=8 word_in_flight=4 
oper_word_size=2
               dd-1259  [000] ....  3383.500107: dspi_fifo_write: 
msg=ffff800011973840 actual_length=13 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] ....  3383.500111: 
dspi_transfer_one_message: returning actual_length=69

bad one:
               dd-1259  [000] ....  3383.500149: 
dspi_transfer_one_message: 0 transfer->length=1
               dd-1259  [000] ....  3383.500172: dspi_fifo_write: 
msg=ffff800011973840 actual_length=1 bytes_sent=1 word_in_flight=1 
oper_word_size=1
               dd-1259  [000] ....  3383.500178: 
dspi_transfer_one_message: 1 transfer->length=3
               dd-1259  [000] ....  3383.500202: dspi_fifo_write: 
msg=ffff800011973840 actual_length=4 bytes_sent=3 word_in_flight=3 
oper_word_size=1
               dd-1259  [000] ....  3383.500207: 
dspi_transfer_one_message: 2 transfer->length=1
               dd-1259  [000] ....  3383.500227: dspi_fifo_write: 
msg=ffff800011973840 actual_length=5 bytes_sent=1 word_in_flight=1 
oper_word_size=1
               dd-1259  [000] ....  3383.500232: 
dspi_transfer_one_message: 3 transfer->length=64
               dd-1259  [000] d.H.  3383.500286: dspi_fifo_write: 
msg=ffff800011973840 actual_length=13 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.H.  3383.500307: dspi_fifo_write: 
msg=ffff800011973840 actual_length=21 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.H.  3383.500327: dspi_fifo_write: 
msg=ffff800011973840 actual_length=29 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.H.  3383.500347: dspi_fifo_write: 
msg=ffff800011973840 actual_length=37 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.H.  3383.500366: dspi_fifo_write: 
msg=ffff800011973840 actual_length=45 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.H.  3383.500385: dspi_fifo_write: 
msg=ffff800011973840 actual_length=53 bytes_sent=8 word_in_flight=2 
oper_word_size=4
               dd-1259  [000] d.H.  3383.500404: dspi_fifo_write: 
msg=ffff800011973840 actual_length=61 bytes_sent=8 word_in_flight=4 
oper_word_size=2
               dd-1259  [000] ....  3383.500436: dspi_fifo_write: 
msg=ffff800011973840 actual_length=13 bytes_sent=8 word_in_flight=4 
oper_word_size=2
               dd-1259  [000] ....  3383.500441: 
dspi_transfer_one_message: returning actual_length=13


-michael

  parent reply	other threads:[~2020-03-17 11:24 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-14 22:43 [PATCH v3 00/12] NXP DSPI bugfixes and support for LS1028A Vladimir Oltean
2020-03-14 22:43 ` [PATCH v3 01/12] spi: spi-fsl-dspi: Don't access reserved fields in SPI_MCR Vladimir Oltean
     [not found] ` <20200314224340.1544-1-olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2020-03-14 22:43   ` [PATCH v3 02/12] spi: spi-fsl-dspi: Fix little endian access to PUSHR CMD and TXDATA Vladimir Oltean
2020-03-14 22:43   ` [PATCH v3 03/12] spi: spi-fsl-dspi: Fix bits-per-word acceleration in DMA mode Vladimir Oltean
2020-03-14 22:43   ` [PATCH v3 04/12] spi: spi-fsl-dspi: Avoid reading more data than written in EOQ mode Vladimir Oltean
2020-03-14 22:43   ` [PATCH v3 05/12] spi: spi-fsl-dspi: Protect against races on dspi->words_in_flight Vladimir Oltean
     [not found]     ` <20200314224340.1544-6-olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2020-03-16 12:35       ` Vladimir Oltean
2020-03-14 22:43   ` [PATCH v3 08/12] spi: spi-fsl-dspi: Fix interrupt-less DMA mode taking an XSPI code path Vladimir Oltean
2020-03-14 22:43   ` [PATCH v3 09/12] spi: spi-fsl-dspi: Move invariant configs out of dspi_transfer_one_message Vladimir Oltean
2020-03-14 22:43   ` [PATCH v3 10/12] spi: spi-fsl-dspi: Add support for LS1028A Vladimir Oltean
2020-03-14 22:43   ` [PATCH v3 11/12] arm64: dts: ls1028a: Specify the DMA channels for the DSPI controllers Vladimir Oltean
2020-03-14 22:43   ` [PATCH v3 12/12] arm64: dts: ls1028a-rdb: Add a spidev node for the mikroBUS Vladimir Oltean
2020-03-14 22:43 ` [PATCH v3 06/12] spi: spi-fsl-dspi: Replace interruptible wait queue with a simple completion Vladimir Oltean
2020-03-16 12:26   ` Mark Brown
     [not found]     ` <20200316122613.GE5010-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2020-03-16 12:29       ` Vladimir Oltean
     [not found]         ` <CA+h21hqRV+HmAz4QGyH9ZtcFWzeCKczitcn+mfTdwAC7ZobdDw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2020-03-16 12:49           ` Mark Brown
2020-03-16 13:00             ` Vladimir Oltean
     [not found]               ` <CA+h21hpoHGuDwpOqtWJFO7+0mQVUrmcBLW7nnGq6dt3QU5axfw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2020-03-16 13:25                 ` Michael Walle
2020-03-16 16:23                   ` Vladimir Oltean
     [not found]                     ` <CA+h21hqt7Xe1LrSDsCVS8zqunQp2tKGhmHDraMirxL595go4nA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2020-03-16 17:15                       ` Michael Walle
     [not found]                         ` <8c22cb70b7c0acb6769e0c68540ab523-QKn5cuLxLXY@public.gmane.org>
2020-03-17 11:24                           ` Michael Walle [this message]
2020-03-14 22:43 ` [PATCH v3 07/12] spi: spi-fsl-dspi: Avoid NULL pointer in dspi_slave_abort for non-DMA mode Vladimir Oltean

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